Contactless replacement for cabled standards-based interfaces

ABSTRACT

A contactless, electromagnetic (EM) replacement (substitute, alternative) for cabled (electric) Standards-based interfaces (such as, but not limited to USB) which effectively handles the data transfer requirements (such as bandwidth, speed, latency) associated with the Standard, and which is also capable of measuring and replicating relevant physical conditions (such as voltage levels) on data lines so as to function compatibly and transparently with the Standard. A contactless link may be provided between devices having transceivers. A non-conducting housing may enclose the devices. Some applications for the contactless (EM) interface are disclosed. A dielectric coupler facilitating communication between communications chips which are several meters apart. Conductive paths may provide power and ground for bus-powered devices.

CROSS-REFERENCE(S) TO RELATED APPLICATIONS

Priority is claimed from U.S. 61/605,981 filed 2 Mar. 2012, incorporatedby reference herein.

This is a continuation-in-part of U.S. Ser. No. 13/427,576 filed 22 Mar.2012 (now US 20120263244), which claims priority from U.S. 61/467,334filed 24 Mar. 2011, incorporated by reference herein.

Priority is claimed from U.S. 61/661,756 filed 19 Jun. 2012,incorporated by reference herein.

This is a continuation-in-part of U.S. Ser. No. 13/713,564 filed 13 Dec.2012, which claims priority from U.S. 61/570,707 filed 14 Dec. 2011,incorporated by reference herein.

This is a continuation-in-part of U.S. Ser. No. 12/655,041 filed 21 Dec.2009 (US 20100159829), which claims priority from U.S. 61/203,702 filed23 Dec. 2008, incorporated by reference herein.

TECHNICAL FIELD

This disclosure relates broadly to techniques for digital communication,particularly Standards-based interfaces, and also relates to systemsincorporating said techniques.

BACKGROUND

Universal Serial Bus (USB) is an example of an interface “Standard” thatdefines the cables, connectors and communications protocols used in abus for connection, communication and power supply between a “host”electronic device (such as a personal computer) or “hub” and variousperipheral electronic devices such as keyboards, pointing devices,digital cameras, printers, portable media players, disk drives, networkadapters, smartphones, and video game consoles.

Conventional USB interfaces uses electrical connectors and cables (withelectrical wires) to interface from the host (alternatively a hub)device to peripheral devices. The connectors are mechanical in nature,and may wear down and eventually fail after repeated use. The existingmechanical connectors, which may be physically different for the hostand peripheral devices, use electrical signaling contacts to communicate(transfer, transport data signals) from one device to another. Theseconnectors must engage one another completely in order to ensure a goodconnection. The electrical signaling is also not ideal as it has manydiscontinuities in the wiring through the connector and wiringassociated with the cable. This imposes an inherent limit on the speedof USB and increases the power budget for successfully transmittingsignal over a significant distance. The length of a USB cable ispractically limited (by cable delays, etc.) to approximately 5 meters.Power may be supplied via the USB connectors and cables to “bus-powered”peripheral devices. Current draw from the bus is normally limited to 100mA or 500 mA.

SUMMARY

What is needed is a “replacement” communications interface for wiredStandards-based interfaces such as USB that reduces or eliminates someof the problems associated therewith, while operating “transparently”within the constraints of the Standard.

It is a general object of the invention to provide improved techniquesfor communicating between electronic devices.

This object may generally be achieved by eliminating mechanicalconnectors and cable wires, using instead “contactless”(electromagnetic) connectors and an electromagnetic (EM) communicationslink (interface). Transceivers and transducers (antennas) for convertingfrom electrical signals to electromagnetic (EM) signals may handle thecommunications between devices. Electrical conditions (such as voltageon differential signal lines) relevant to the successful operation ofthe Standard may be detected at a transmitting device and sent (such asout-of-band) over the electromagnetic (EM) interface to a receivingdevice. Arrangements for delivering power to a “bus-powered” downstreamdevice are also disclosed. The techniques disclosed herein may beconsidered to be a contactless “replacement” for cabled Standards-basedinterfaces.

According to the invention, generally, a contactless, electromagnetic(EM), radio frequency (RF) communications link may be establishedbetween two or more electronic devices (one of which may function as ahost or hub) which ordinarily communicate with one another via aStandards-based interface or wired (cable-connected) communications linkor protocol (such as, but not limited to USB). A system may comprisemany communications links connecting the host to many devices. Thecontactless link disclosed herein may link may replicate or emulate (orreplace, or be substituted for) an existing wired communications link(such as, but not limited to USB) so as to be transparently substitutedfor at least one of the communications links in an overall system. Thismay include transporting data between devices, providing power todevices, communicating characteristics of devices to a hub or host,within the constraints (such as timing) of the protocol.

In the main hereinafter, a contactless communications link for replacinga USB link will be discussed, as exemplary of any of a number ofStandards-based interfaces which may have one or more of their cabledcommunications links replaced by the contactless communications linkdisclosed herein. These Standards-based interfaces may include, but arenot limited to PCIe, SATA, SAS, MHL, HDMI, DP, Ethernet, I2S, I2C,Thunderbolt, Quickpath, D-PHY, M-PHY, Hypertransport, and the like.

The solution presented herein solves the problem of transmitting nativeUSB (as an example of any Standards-based protocol) over a contactlessconnector by converting electrical signaling conditions on a first USBdevice into an electromagnetic signal and transmitting the signalthrough a contactless connector to a receiver on a second USB device(which may be a host or hub). The second device converts theelectromagnetic signal into electrical signals and replicates theelectrical signaling conditions from the first device at the seconddevice. By replicating (regenerating, recreating) the electricalconditions and operating within the timing constraints of the protocol,it may appear to the second device that the first device is physicallyconnected (such as via an electrical cable and physical connectors) tothe system bus.

The electromagnetic (EM) signal may be in the EHF range of frequencies,such as from 30 to 300 gigahertz, or higher. The EM signal may bepropagated over a short distance, such as on the order of only onecentimeter (1 cm). A dielectric medium, such as plastic, may be used toextend the range of the EM signal, such as beyond a few centimeters (cm)to many meters.

The conversion to and from electromagnetic (EM) signals occurs in a veryshort (sub ns) period of time. By replicating the electrical signalingconditions from the first USB device to the second USB device and doingso in a very short period of time, the contactless connector isinvisible to both the first USB device and the second USB device and thedevices behave as if they were connected electrically.

According to the invention, generally, a contactless, electromagnet (EM)replacement (substitute, alternative) for cabled (electric)Standards-based interfaces (such as, but not limited to USB) whicheffectively handles the data transfer requirements (such as bandwidth,speed, latency) associated with the Standard, and which is also capableof measuring and replicating relevant physical conditions (such asvoltage levels) on data lines so as to function compatibly andtransparently with the Standard. A contactless link may be providedbetween devices having transceivers. A non-conducting housing mayenclose the devices. Some applications for the contactless (EM)interface are disclosed. A dielectric coupler facilitating communicationbetween communications chips which are several meters apart. Conductivepaths may provide power and ground for bus-powered devices.

According to some embodiments of the invention, a method ofcommunicating data may comprise: at a first device, determining anelectrical condition of a first set of signal lines carrying data, andtransmitting an electromagnetic (EM) signal indicative of the electricalcondition associated with the data; wherein the signal lines may beconfigured for transporting a Standards-based protocol which is designedfor communicating electrical signals over a physical link. The firstdevice may receive an electromagnetic signal indicative of a secondelectrical condition associated with data originated on second set ofsignal lines at a second device, and may replicate the second electricalcondition at the first device. A second device may receive theelectromagnetic signal indicative of the electrical condition and mayreplicate a similar electrical condition on a second set of signallines. The first and second devices may be connectedelectromagnetically, rather than physically connected with one another,such as over an air gap or through one or more dielectric mediums,including through a dielectric cable, over an electromagnetic interfacein an extremely high frequency (EHF) band, such as by modulating anddemodulating a carrier having a frequency of at least 30 GHz(gigahertz). The electromagnetic signal may be transmitted withincriteria established by a Standards-based protocol, and may betransmitted with an energy output below that of FCC requirements fortransmitting an identification code. The device(s) may be enclosed witha non-conducting barrier which may also hermetically seal the device(s).

The Standards-based protocol may be selected from the group consistingof USB, PCIe, SATA, SAS, MHL, HDMI, DP, Ethernet I2S, I2C, Thunderbolt,Quickpath, D-PHY, M-PHY, Hypertransport, and the like.

According to some embodiments of the invention, a system forcommunicating data from signal lines configured for a Standards-basedprotocol which is designed for communicating electrical signals over aphysical link may be characterized in that a first device may comprise:means for converting electrical signal inputs into electromagnetic (EM)signal outputs to support an extremely high frequency (EHF) contactlesscommunication link; and means for determining an electrical condition ofa first set of signal lines carrying data and for transmitting anelectromagnetic (EM) signal indicative of the electrical conditionassociated with the data. The device may further comprise means forreceiving an electromagnetic signal indicative of a second electricalcondition associated with data originated on second set of signal linesat a second device, and for replicating the second electrical conditionat the first device. The second device may comprise means for receivingthe electromagnetic signal indicative of the electrical condition andreplicating a similar electrical condition on a second set of signallines. A non-conducting barrier may enclosing the device(s).

Some benefits or advantages to the communications interface techniquesdisclosed herein may include one or more of the following:

-   -   transparent to USB and other protocols    -   eliminates the need for mechanical connectors    -   can be used in existing systems with existing interfaces such as        USB and other protocols low latency    -   low cost, semiconductor-based connector solution    -   no software required    -   high bandwidth (up to 10 Gbps and beyond)    -   low power    -   allows for new form factors while maintaining compatibility with        existing Standards    -   allows for completely enclosed devices    -   provides superior ESD (electrostatic discharge) protection for        Standard interfaces    -   contactless connectors do not have to be touching and can move        around relative to each other

Energy output by the devices may be in the EHF band, below FCCrequirements for certification or for transmitting an identificationcode which would otherwise interrupt data flow, which eliminates theneed to interrupt data flow to send such an ID. Reference is made to 47CFR §15.255 (Operation within the band 57-64 GHz), incorporated byreference herein.

The invention(s) described herein may relate to industrial andcommercial industries, such as electronics and communications industriesusing devices that communicate with other devices or devices havingcommunication between components in the devices.

Other objects, features and advantages of the invention(s) disclosedherein may become apparent in light of the following illustrations anddescriptions thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made in detail to embodiments of the disclosure,non-limiting examples of which may be illustrated in the accompanyingdrawing figures (FIGs). The figures may be in the form of diagrams. Someelements in the figures may be exaggerated or drawn not-to-scale; othersmay be omitted, for illustrative clarity. Any text (legends, notes,reference numerals and the like) appearing on the drawings areincorporated by reference herein. When terms such as “left” and “right”,“top” and “bottom”, “upper” and “lower”, “inner” and “outer”, or similarterms are used in the description, they may be used to guide the readerto orientations of elements in the figures, but should be understood notto limit the apparatus being described to any particular configurationor orientation, unless otherwise specified or evident from context.

FIG. 1 is a generalized block diagram of a physical (wired) linkimplementing a Standards-based protocol, such as USB to connect devices(one of which may be a “host”).

FIG. 2 is a generalized block diagram of a contactless link forreplacing at least some of the functionality of the physical link shownin FIG. 1, connecting the devices via electromagnetics (EM).

FIG. 3 is a diagram illustrating an electromagnetic (EM) communicationslink operating over a “plastic cable”.

FIG. 4 is a block diagram illustrating a communications link oftransceivers and power connectors between two devices.

FIG. 5 is a flowchart illustrating operation of an exemplarytransceiver.

FIGS. 6A, 6B are diagrams illustrating exemplary deployment modes.

DETAILED DESCRIPTION

Various embodiments may be described to illustrate teachings of theinvention(s), and should be construed as illustrative rather thanlimiting. It should be understood that it is not intended to limit theinvention(s) to these particular embodiments. It should be understoodthat some individual features of various embodiments may be combined indifferent ways than shown, with one another.

The embodiments and aspects thereof may be described and illustrated inconjunction with systems, devices and methods which are meant to beexemplary and illustrative, not limiting in scope. Specificconfigurations and details may be set forth in order to provide anunderstanding of the invention(s). However, it should be apparent to oneskilled in the art that the invention(s) may be practiced without someof the specific details being presented herein. Furthermore, well-knownfeatures may be omitted or simplified in order not to obscure thedescriptions of the invention(s).

Reference herein to “one embodiment”, “an embodiment”, or similarformulations, may mean that a particular feature, structure, operation,or characteristic described in connection with the embodiment, isincluded in at least one embodiment of the present invention. Thus, theappearances of such phrases or formulations herein are not necessarilyall referring to the same embodiment. Furthermore, various particularfeatures, structures, operations, or characteristics may be combined inany suitable manner in one or more embodiments.

In the following descriptions, some specific details may be set forth inorder to provide an understanding of the invention(s) disclosed herein.It should be apparent to those skilled in the art that theseinvention(s) may be practiced without these specific details. In otherinstances, descriptions of well-known steps or components, may bedescribed only generally, or even omitted, in order to not obscure theinvention(s) being described. Headings (typically underlined) may beprovided as an aid to the reader, and should not be construed aslimiting.

Some Terminology

The following terms may be used in the descriptions set forth herein,and should be given their ordinary meanings unless otherwise explicitlystated or as may be evident from context.

The acronym “EHF” stands for Extremely High Frequency, and refers to aportion of the electromagnetic (EM) spectrum in the range of 30 GHz to300 GHz (gigahertz).

The term “transceiver” (abbreviated “XCVR”) may refer to a device suchas an IC (integrated circuit) including a transmitter and a receiver sothat that integrated circuit may be used to both transmit and receiveinformation (data). Generally, a transceiver may be operable in ahalf-duplex mode (alternating transmitting and receiving), a full-duplexmode (transmitting and receiving simultaneously), or both.

The term “contactless”, as used herein, refers to implementingelectromagnetic (EM) rather than electrical (wired, contact-based)connections and transport of signals between entities (such as devices).In some of the literature, the term “wireless” is used to convey thismeaning. As used herein, the term “contactless” may refer to acarrier-assisted, dielectric coupling system which may have an optimalrange in the near-field of the EM signal. The connection may bevalidated by proximity of one device to a second device. Multiplecontactless transmitters and receivers may occupy a small volume ofspace. A contactless link established with electromagnetics (EM) may bepoint-to-point in contrast with a wireless link which typicallybroadcasts to several points.

The terms “Standards” (and “Standards-based”), as used herein, refer tocommunications interfaces and protocols such as, but not limited to,USB, PCIe, SATA, SAS, MHL, HDMI, DP, Ethernet I2S, I2C, Thunderbolt,Quickpath, D-PHY, M-PHY, Hypertransport, and the like, any of which mayhave data format requirements and constraints, as well as beingresponsive to and creating physical conditions (such as voltage levels)upon a physical, electrical interface or communications link betweenelectronic devices.

The terms, chip, die, integrated circuit (IC), semiconductor device, andmicroelectronic device, are often used interchangeably, in common usage,and may be used interchangeably herein. This also may include bare chips(or dies), packaged chips (or dies), and chip modules and packages.

Some functions described as being implemented by chips may beimplemented as macro-functions incorporated into application specificintegrated circuits (ASICS) and the like, and may alternatively beimplemented, at least partially, by software running on amicrocontroller. For example, “bit banging” is a technique for serialcommunications using software instead of dedicated hardware. Softwaredirectly sets and samples the state of pins on the microcontroller, andis responsible for all parameters of the signal: timing, levels,synchronization, etc. Bit banging may allow a given device to usedifferent protocols with minimal or no hardware changes required.

With respect to chips, various signals may be coupled between them andother circuit elements via physical, electrically-conductiveconnections. Such a point of connection is may be referred to as aninput, output, input/output (I/O), terminal, line, pin, pad, port,interface, or similar variants and combinations.

An Exemplary Standards-Based Physical Interface

FIG. 1 illustrates a physical communications link 100 between a firstelectronic device 110 and a second electronic device 120. The firstdevice 110, for example, may be a personal computer (PC). The seconddevice 120, for example, may be a computer peripheral (printer,keyboard, etc). A cable 130 is shown connecting the two devices with oneanother for transporting signals, electrically, between the two devices.

As used herein, the term “Physical Interface” means that signals (andoptionally power) are transported between the devices electrically overwires (in a cable), and mechanical connectors may be used to connect thecable to the devices 110 and 120.

USB may be used throughout the descriptions set forth herein as anexample of a Standards-based protocol. The USB bus is based on aso-called ‘tiered star topology’ in which there is a single “host”device and up to 127 “peripheral” devices. (“Hub” devices operatesimilar to host devices.) In this example, the first electronic device110 may function as the “host” and the second electronic device 120 maybe a representative peripheral device.

The first device 110 has a USB bus controller 112 connected to aninternal (to the device 110) data bus 114 and manages the conversion ofthe data from a data bus 114 to an appropriate USB format. (If thecontroller 112 is implemented as a system on chip (SOC), the lines 114may be internal to the controller 112.) The controller 112 includestransceivers (not shown). In a transmit mode, data in USB format isprovided by the controller 112, via electrically conductive signal(data) lines 118 (such as traces on a printed wiring board), to amechanical connector 116. (Two of the lines 118 may be for power andground, and may originate other than at the controller 112.) In areceive mode, data in USB format is provided by the connector 116 to thecontroller over the signal lines 118.

The second device 120 has a USB bus controller 122 connected to aninternal (to the device 110) data bus 124 and manages the conversion ofthe data from a data bus 124 to an appropriate USB format. (If thecontroller 122 is implemented as a system on chip (SOC), the lines 124may be internal to the controller 122.) The controller 122 includestransceivers (not shown). In a transmit mode, data in USB format isprovided by the controller 122, via electrically conductive signal(data) lines 128 (such as traces on a printed wiring board), to amechanical connector 126. (Two of the lines 128 may be for power andground, and may originate other than at the controller 122.) In areceive mode, data in USB format is provided by the connector 126 to thecontroller over the signal lines 128.

A cable 130 is provided for transporting signals (and optionally power),electrically, between the two devices 110 and 120. An “upstream”mechanical connector 132 is disposed at one end of the cable 130 andconnects electrically with the connector 116 at the host device 110 A“downstream” mechanical connector 134 is disposed at the other end ofthe cable 130 and connects electrically with the connector 126 at theperipheral device 120. The cable 130 has a number of electricallyconductive paths (typically wires), and establishes a physical(electrical) link between the first device 110 and the second device120.

In an exemplary (pre-USB3.0) format, the cable 130 comprises a twistedpair of wires 136 a and 136 b (which may collectively referred to as“136”) constituting a differential transmission pair of wires(designated “D+” and “D−”), and another pair of wires 138 a and 138 b(which may collectively be referred to as “138”) for providing power (inUSB, VBUS) and ground (GND), respectively for bus-powered peripheraldevices). In USB3.0, two additional pairs of wires (superspeedtransmitter SSTX and superspeed receiver SSRX differential pairs, notshown) and an additional ground (GND_DRAIN, not shown) are added toaugment capability (greater bandwidth, etc.) of the physical link. Thedifferential pair(s) of wires 136 conveying signals may be referred tohereinafter simply as “data lines”, the other wires 138 may be referredto as “power lines”. In the main hereinafter, pre-USB3.0 will bediscussed as exemplary of a Standards-based physical link.

The USB specification defines four data speeds (transfer rates): LS/LowSpeed (1.5 Mbit/s), FS/Full Speed (12 Mbit/s), HS/High Speed (480Mbit/s), and SS/SuperSpeed (5 Gbit/s) data speed. These speeds are thefundamental clocking rates of the system, and as such do not representpossible throughput, which will always be lower as the result of theprotocol overheads.

Transceivers (not shown) may be provided at both ends of a data link (inthe hub or host, and in the connected device) for providing(transmitting) signals onto the data lines 138 (D+/D−), and detecting(receiving) signals from the data lines 138. A typical upstream end (endnearer the host) transceiver has two 15K pull-down resistors. Whentransmitting, each data line (D+ and D− can be driven low individually,or a differential data signal can be applied. When receiving, individualreceivers on each line are able to detect single ended signals, so thatthe so-called Single Ended Zero (SEO) condition, where both lines arelow, can be detected. There is also a differential receiver for reliablereception of data.

Enumeration is the term given to establishing what types of devices areconnected to the USB bus, in terms of their characteristics, such as thedata speed(s) of the device(s) that are connected to the bus (such asLow, Full, High, SuperSpeed). To function successfully, a device mustdetect and respond to any control request or other bus event at anytime.

In an exemplary sequence of events, a user attaches a device to a USBport, or the system powers up with a device attached. The port may be onthe root hub at the host or on a hub that connects downstream from thehost. The hub detects the device, and monitors the voltages on thesignal lines (D+ and D−) at each of its ports. The hub has a pull-downresistor of 14.25 k-24.8 kΩ on each line.

At the (peripheral) device end of the link a 1.5 kΩ (kilo-ohm) resistorpulls one of the data lines (D+ or D−) up to a 3.3V supply derived fromVBUS. The “pull-up” resistor is applied to the D− line for a low speeddevice, and is applied to the D+ for a full speed device. (A high speeddevice will initially present itself as a full speed device with thepull-up resistor on D+.) The host can determine the required speed byobserving which of the data lines (D+ or D−) is pulled high.

The above description of USB is provided merely as an example of acommunication link that is a physical (wired) link, exchanges databetween devices, and also imposes and detects physical conditions on thelink which are indicative of characteristics of the devices relevant toefficient operation of the link (or bus). Other examples of similar (forpurposes of the present disclosure) may include PCIe, SATA, SAS, MHL,HDMI, DP, Ethernet, I2S, I2C, Thunderbolt, Quickpath, D-PHY, M-PHY,Hypertransport, and the like.

Converting a Standards-Based Physical Interface to a ContactlessInterface

A USB interface (communications link) has been described above asexemplary of a number of communications links which communicate over aphysical interface of cables (wires) and electrical connectors.

Connector-replacement chips and some implementations of contactless(sometimes referred to as wireless) links have also been described. Thetechniques disclosed in the '829 and '244 publications are directed atconverting electrical signals to electromagnetic (EM) signals,propagation characteristics for the EM signals, antenna designconsiderations and packaging features.

As mentioned above, the exemplary USB interface relies upon imposing anddetecting physical conditions on the link which are indicative ofcharacteristics of the devices relevant to efficient operation of thelink (or bus). The USB Standard also imposes constraints, such as timingrequirements, on transmission of signals.

It is an object of this disclosure to provide a contactless (EM)replacement (substitute, alternative) for cabled (electric)Standards-based interfaces (such as, but not limited to USB) whicheffectively handles the data transfer requirements and criteria (such asbandwidth, speed, latency) associated with the Standard, and which isalso capable of effectively replicating the relevant physical conditions(such as measuring and imposing voltage levels on data lines, applyingresistances to the data lines, providing power and ground to lines,etc.) and characteristics (such as protocol timing requirements, busturnaround requirements) of the physical link being replaced.

By eliminating electrical connectors and cables, and transporting datausing electromagnetics (EM), higher performance interfaces may berealized, while maintaining the benefits and capabilities of theunderlying Standards-based protocol being replaced. The substitution ofan electromagnetic (EM) link for the otherwise electrical one should berobust, flexible and versatile to handle protocols other than USB,including but not limited to PCIe, SATA, SAS, MHL, HDMI, DP, EthernetI2S, I2C, Thunderbolt, Quickpath, D-PHY, M-PHY, Hypertransport, and thelike, some of which have similar problems which may be solved in similarways.

The US 20100159829 ('829 publication) and US 20120263244 ('244publication), for example, contemplated electrical signaling. U.S.61/661,756 ('756 application) provides disclosure of a non-electricalmedium (“plastic cable”) capable of transporting electromagnetic (EM)signals (and, additionally, some electrical signals) a considerabledistance (up to kilometers, and more).

By using electromagnetics (EM) rather than electrical cables andconnectors to establish the data link, many of the problems associatedwith the physical implementation of the link may be avoided, such asmechanical wear, customer returns due to broken connectors, as well asbandwidth (data transfer rate) and limitations on the length of thelink. Moreover, the use of an EM link rather than electrical cablingallows devices to be completely sealed, such as against environmentalfactors, including ESD (electrostatic damage).

Additionally, limitations inherent in the physical interface beingreplaced (such as signal degradation at discontinuities in a physicalsignal path, such as from chip-to-PCB, PCB-to-connector,connector-to-cable, which may act as low pass filters) may be avoided,and consequently data transfer rates may be higher, bandwidth may beincreased, and the length (range) of the link may exceed that of thephysical interface being replaced.

Previous attempts to solve the problem(s) associated with physicalinterfaces have involved wireless communications, such as WiFi or WiGig,better connector and conductor technologies, equalization to improve thesignaling, and complex signaling schemes to improve the bandwidth andS/N ratio. These attempts may have the following negative attributes:

-   -   WiFi: Higher power, Higher cost, lower bandwidth, long latency,        software complexity    -   WiGig: Higher power, Much higher cost, low bandwidth relative to        USB3, long latency, software complexity    -   Generally, all wireless technologies are fundamentally insecure,        because they broadcast their communications signals, allowing        interception by unauthorized users, therefore typically        requiring encryption which increases the latency of the        connection.    -   Better Connectors: Higher cost, still have mechanical and return        issues, performance is still limited

The techniques disclosed herein may be implemented with integratedcircuits (ICs) using standard CMOS(Complementary-Metal-Oxide-Semiconductor) processes. The ICs may converta standard USB input (USB, USB2, USB3) into a electromagnetic (EM)carrier. This conversion may be done with very low latency and istransparent to the underlying protocol. The electromagnetic (EM) signalmay be in the EHF (Extremely High Frequency) band, or higher, and may bepropagated through air, or conducted through plastic waveguides and/ordirected using reflective materials. The EM carrier may be generated inone device or peripheral and may be transmitted through a short distanceof air to the receiver in a companion device or peripheral.

Conventional Standards-protocols such as USB use electrical signals tocommunicate between two devices. The electrical signals may be atdifferent levels indicating logical values such as “1” or “0”. Theelectrical signals may also include many other characteristics such astermination resistance, drive strength, status/configuration, and drivetype. Some of these characteristics are used in USB and similar otherprotocols for functions such as enumeration, power state information, orwhether a device is connected or not.

One design challenge of the “contactless” USB (or similar otherprotocol) interface is to appear transparent to existing USB devices andperipherals. In order to accomplish this, the electrical levels,characteristics, and conditions must remain largely the same between thetwo devices even though they are not physically connected. Thecontactless solution presented here replicates those conditions at bothdevices by measuring and capturing the current electrical conditionsassociated with the data and transmitting (conveying) those conditionsfrom one device to the other.

At the receiving device, the electrical conditions may be recreated sothat the two USB devices have similar electrical conditions on theirinputs and outputs as if they had been physically connected. In someimplementations, the receiver may deduce (infer, determine) theappropriate electrical conditions based on the current state of theelectrical interface at the receiver, the current state of a statemachine at the receiver, and/or data that is being transmitted orreceived over the electromagnetic (EM) interface, or combinationsthereof. Therefore, in some cases, the transmitter may only need totransmit a subset (or a representation) of the electrical conditionspresent at the transmitter. In some implementations, the subset (orrepresentation) may be reduced to the logical level (logic “1” or logic“0”) of the electrical interface. The state machine may track thecurrent mode or state of operation of the transmitter or the receiver.This may be used in conjunction with the actual electrical conditions atthe transmitter or the receiver, or with data received over theelectromagnetic interface to generate the appropriate electricalconditions at the receiver.

Generally, an electromagnetic (EM) link may replace an electrical (wire)link such as USB and similar protocols (Standards-based interfaces) toconnect two (or more) devices, one of which may be a host or hub, theother(s) of which are “connected devices”. In addition to performingdata transfer between the devices, electrical characteristics andconditions relevant to operation of the protocol such as line voltages,termination resistance, drive strength, status/configuration, and drivetype may be measured at one device, then transmitted to and recreated atanother device, such as a hub or host. The conversion from electrical toelectromagnetic (EM), and transmission of data and electrical conditionsmay be may be done with very low latency so as to be transparent to theunderlying protocol. In some implementations, the receiver may deduce(infer, determine) the appropriate electrical conditions based on thecurrent state of the electrical interface at the receiver, the currentstate of a state machine at the receiver, and/or data that is beingtransmitted or received over the electromagnetic (EM) interface, orcombinations thereof, as described above.

The two devices can communicate to each other without a physicalconnection and can also communicate over a dielectric medium. Thedevices can be protected using a non-conducting medium, thus affordingsupplier ESD protection to Standards-based interfaces.

Another challenge is the enumeration phase of many of the Standards suchas USB. In the enumeration phase, some electrical characteristics andconditions are tested and measured by the host (Device A) or connecteddevice (Device B). These electrical characteristics and conditions maydetermine the type or mode of operation of the Standards-basedinterface. It may be important that the conditions on both sides of thelink be largely similar. This invention allows for the correct andproper enumeration of Standards-based interfaces even though they arenot connected by replicating the electrical characteristics andconditions on both sides of the link.

The invention also provides transparency to Standards-based protocols bytransmitting and receiving the electrical characteristics and conditionsin a very small (such as sub-nanosecond) period of time which thecontactless interface to appear (such as to USB controllers which havetight timing constraints) as if it were directly (physically) connected.Transparency may be provided by transmitting or by receiving theelectrical characteristics, and reproducing (recreating, replicating,duplicating) the electrical conditions based on simple states. This canbe done at the transmitter, at the receiver, or both.

Connector-Replacement Chips

US 20100159829 (the '829 publication), incorporated in its entirety byreference herein, discloses tightly-coupled near-fieldcommunication-link devices, referred to therein as“connector-replacement chips”. Tightly-coupled near-fieldtransmitter/receiver pairs are deployed such that the transmitter isdisposed at a terminal portion of a first conduction path, the receiveris disposed at a terminal portion of a second conduction path, thetransmitter and receiver are disposed in close proximity to each other,and the first conduction path and the second conduction path arediscontiguous with respect to each other. In this manner, methods andapparatus are provided for transferring data through a physicallydiscontiguous signal conduction path without the physical size andsignal degradation introduced by a signal-carrying mechanical connector,and associated cabling. The '829 publication references U.S. Pat. No.5,621,913 (Micron, 1997), which is also incorporated in its entirety byreference herein.

The '829 publication shows (FIG. 12 therein) a high-level block diagramof the transmit path of a near-field transmitter. An equalizer receivesan input signal and compensates for strip-line loss; an EHF carriergenerator, either free-running or locked to a reference extracted fromthe data input, is coupled to a modulator; and an antenna interface iscoupled to the modulator, the antenna interface typically including animpedance matching network and a final output driver coupled to anantenna.

The '829 publication shows (FIG. 13 therein) a high-level block diagramof the receive path of a near-field receiver. An antenna is coupled to areceiver that has sufficient sensitivity and signal-to-noise ratio tomaintain an acceptable bit-error-rate; the receiver is coupled to an EHFlocal oscillator and to a demodulator. The demodulator is coupled to aline-driver that provides equalization appropriate for the desired datarate.

US 20120263244 (the '244 publication), incorporated in its entirety byreference herein, discloses integrated circuit with electromagneticcommunication. A system for transmitting or receiving signals mayinclude an integrated circuit (IC), a transducer operatively coupled tothe IC for converting between electrical signals and electromagneticsignals; and insulating material that fixes the locations of thetransducer and IC in spaced relationship relative to each other. Thesystem may further include a lead frame providing external connectionsto conductors on the IC. An electromagnetic-energy directing assemblymay be mounted relative to the transducer for directing electromagneticenergy in a region including the transducer and in a direction away fromthe IC. The directing assembly may include the lead frame, a printedcircuit board ground plane, or external conductive elements spaced fromthe transducer. In a receiver, a signal-detector circuit may beresponsive to a monitor signal representative of a received firstradio-frequency electrical signal for generating a control signal thatenables or disables an output from the receiver.

The '244 publication discloses that tightly-coupled transmitter/receiverpairs may be deployed with a transmitter disposed at a terminal portionof a first conduction path and a receiver disposed at a terminal portionof a second conduction path. The transmitter and receiver may bedisposed in close proximity to each other depending on the strength ofthe transmitted energy, and the first conduction path and the secondconduction path may be discontiguous with respect to each other. Inexemplary versions, the transmitter and receiver may be disposed onseparate circuit carriers positioned with the antennas of thetransmitter/receiver pair in close proximity.

The '244 publication discloses that a transmitter or receiver may beconfigured as an IC package, in which an antenna may be positionedadjacent to a die and held in place by a dielectric or insulatingencapsulation or bond material. A transmitter or receiver may beconfigured as an IC package, in which an antenna may be positionedadjacent to a die and held in place by encapsulation material of thepackage and/or a lead frame substrate. Examples of EHF antennas embeddedin IC packages are shown and described.

An Exemplary Contactless Communications Link

FIG. 2 shows a basic implementation of a system comprising a“contactless” link 200 which may serve as a “replacement” for thephysical link 100 between a first device 210 (compare 110) and one (ormore) second devices 220 (compare 120). The contactless link 200 may beimplemented so as to be transparent to a Standards-based communicationsprotocol, such as (but not limited to) USB. As used herein, the term“Contactless Interface” means that signals flowing between the devices210 and 220 occurs electromagnetically over a non-electrical medium 230such as an air gap, waveguide or plastic, for example, as discussed ingreater detail hereinbelow. (The electromagnetic communication over anair gap may be limited to a short range, such as 1-5 cm. The use of adielectric medium such as a plastic cable, described in greater detailhereinbelow, may extend the range significantly, such as many meters.)In the main, hereinafter, data flow from the device 210 to the device220 may be described, as representative of data flow in either direction(i.e., including data flow from the device 220 to the device 210). Itshould be understood that in this, and any other embodiments ofcontactless links discussed herein, an overall communications may beimplemented as a combination of contactless and physical links.

The first device 210 has a USB bus controller 212 (compare 112)connected to an internal data bus 214 (compare 114) and manages theconversion of data from the data bus 214 to an appropriate USB formatonto a set of data (signal) lines 218 a and 218 b (which maycollectively be referred to as “218”). Only two data lines 218 areshown, and may be representative of USB “D+” and “D−” differentialsignal lines. The signal lines 218 (and 228) are configured fortransporting a Standards-based protocol, such as, but not limited toUSB. (USB is referenced merely as an example of a Standards-basedprotocol. In FIG. 1, VBUS and GND lines were also illustrated. Thesignal lines 218 may be transporting any Standards-based protocol, suchas USB, PCIe, SATA, SAS, I2S, etc. It may be noted that in USB-3, andother similar protocols, Tx and Rx may be provided as two separate setsof data lines.) Depending on the protocol being “converted” forelectromagnetic transmission (and reception), there may be several moredata lines 218. The terms “data lines” and “signal lines” may be usedinterchangeably herein, unless otherwise dictated by context. If thecontroller 212 is implemented as a system on chip (SOC), the lines 214may be internal to the controller 212.

The first device 210 is shown having two transceivers (“XCVR”) 216 a and216 b (which may collectively be referred to as “216”) connected to thedata (signal) lines 218 a and 218 b, respectively. These transceivers216 will take the electrical signals from the data lines 218 and convertthem to electromagnetic (EM) signals, such as in the manner described inthe '829 and '244 publications, functioning as “connector replacementchips”, so that the electrical signals of a Standards-based protocol maybe converted to electromagnetic (EM) signals and conveyed between thetwo devices 210 and 220, via the non-electrical medium 230. Pulse CodeModulation (PCM) may be employed to modulate the data onto the carrier,using PCM encoders and decoders (not shown). Out-of-band (OOB) signalingmay be used to convey information other than the data between the twodevices 210 and 220, over the medium 230. Antennas associated with thetransceivers are omitted, for illustrative clarity (they are discussedin detail in the '829 and '244 publications).

In a manner similar to the first device 210, the second device 220(compare 120) has a USB bus controller 222 (compare 122) connected to aninternal data bus 224 (compare 124) and manages the conversion of datafrom the data bus 224 to an appropriate USB format onto a set of datalines 228 a and 228 b (which may collectively be referred to as “228”).Again, only two data lines 228 are shown, and may be representative ofUSB “D+” and “D−” differential signal lines. And the second device 210is shown having two transceivers (“XCVR”) 226 a and 226 b (which maycollectively be referred to as “226”) connected to the data lines 228 aand 228 b, respectively, for receiving electromagnetic (EM) signals fromthe non-electrical medium 230 and converting them to electrical signalswhich are conveyed to the controller 222 over the data lines 228. If thecontroller 222 is implemented as a system on chip (SOC), the lines 224may be internal to the controller 222.

Data transport may be provided (for example) by a synchronous one-bitinterface, where the transceivers 214 and 224 strobe single bits in andout in response to a clock signal within the timing constraints of theStandards-based interface (such as, but not limited to USB).Communication between the devices 210 and 220 may be half-duplex or fullduplex. And, for USB, generally (again, by way of example only) thetransactions between devices may be at Low Speed (LS), Full Speed (FS),High Speed (HS) or SuperSpeed (SS).

In a broad sense, the transceivers 214 and 224 can be thought of asperforming a function similar to that of repeaters. (A repeater is anelectronic device that receives a signal and retransmits it at a higherlevel or higher power, or onto the other side of an obstruction, so thatthe signal can cover longer distances.) However, repeaters are designedto receive a signal and re-transmit it in the same format. In contrasttherewith, using the techniques disclosed herein, the communicationsdevices (transceivers 216 and 218) are capable of receiving signals fromwires, in an electrical format, and converting/transmitting them in anelectromagnetic (EM) format, such as in the EHF band, which mayfacilitate a data rate greater than or equal to 1 Gbps. (Thetransceivers of course enable the reverse situation—receiving signals inEM format and converting them to an electrical format for insertion on aphysical data bus.)

A dashed line 240 is shown around the device 220, as exemplary of anon-conducting barrier (housing, enclosure, or the like), such as ofplastic or acrylic, enclosing the chips (communications devices,transceivers) and or the device (PC, etc) they are in. (This would applyas well to the device 210.) Electromagnetic (EM) radiation may passeasily through the barrier 240, but electrical current cannot passeasily through the barrier 240. The barrier 240 can therefore isolatecircuit board and fragile chips from ESD (electrostatic discharge). Thebarrier 240 may also hermetically seal the device. The barrier 240 mayadditionally provide a benefit to devices such as cell phones, forexample protecting them from moisture and humidity. The electromagneticinterface (EM) techniques disclosed herein may completely eliminate theneed for any mechanical connectors (other than, perhaps a jack forrecharging an internal battery) or other openings in the device.

In addition to simply transporting the data, the Standards-basedinterface may depend upon actual physical characteristics of theinterface to operate efficiently. For example, the USB protocoldiscusses the use of resistors to establish certain voltage levels,selectively, on the data lines (D+/D−) to indicate and initiatedifferent modes of operation. In other words, it may not be sufficientto simply convert the data signals from an electrical format to anelectromagnetic format and transmit them (bit-for-bit) over theelectromagnetic medium, it may also be important to replicate variouselectrical conditions of the communication system in order for theprocess to function effectively and “transparently”.

In order to accomplish the objective of replicating the physicalconditions of the transmission (data) lines, components may be includedin the transceivers 214 and 224, or provided separately, to measure atleast one physical condition (such as, but not limited to voltage level)of at least one of the data lines 218 or 228 in one of the devices 210or 220, and provide a signal indicative of the measured condition to therespective transceiver for transmission (such as OOB) to the other ofthe devices 210 or 220, so that a similar physical condition can bereplicated on a corresponding data line 218 or 228 in the other device.In some implementations, the receiver may deduce (infer, determine) theappropriate electrical conditions based on the current state of theelectrical interface at the receiver, the current state of a statemachine at the receiver, and/or data that is being transmitted orreceived over the electromagnetic (EM) interface, or combinationsthereof, as described previously.

As mentioned above, some peripheral devices may be “bus-powered”,deriving their operating current from the physical (electrical)communications link (in USB, the cable). Having “replaced” thephysical/electrical communications link (130) with an electromagnetic(EM) link 230, power and ground may be included other thanelectromagnetically, as described in greater detail below.

Dielectric Couplers for EHF Communications

U.S. 61/661,756 ('756 application) discloses devices, systems, andmethods for EHF communications, including communications usingdielectric guiding structures and beam focusing structures.

FIG. 3 shows a dielectric coupler 300 for facilitating propagation ofpolarized EHF-frequency signals may include an elongate strip ofdielectric material (medium) 302 such as plastic, glass, rubber orceramic, and may have a rectangular cross section and two ends. Thedielectric medium may be referred to as a “plastic cable”, and mayfunction as the non-electrical medium 230. Suitable plastic materialsfor the dielectric medium 302 may include, but are not limited to, PE(polyethylene), acrylic, PVC (polyvinylchloride), ABS(Acrylonitrile-Butadiene-Styrene), and the like

In its signal-conveying capacity (as a signal path), the plastic cablemay be considered to be a “virtual wire”. Stacked or layered dielectriccoupler structures may enable multiple signal paths, such as to besubstituted for the exemplary twisted pair of physical wires in theexemplary USB bus.

The dielectric coupler 300 may facilitate communication betweencommunications chips (transceivers) 316 and 326 (compare 216 and 226) ata transmission source and a transmission destination, respectively. Atransmit transducer 312 operatively coupled with the communication chip316 may be disposed at one end of the dielectric coupler 300. A receivetransducer 322 operatively coupled with the communication chip 326 maybe disposed at the other end of the dielectric coupler 300. Thesetransducers (or antennas) 312 and 322 may be disposed adjacent ends ofthe dielectric medium 302, in close proximity thereto, and coupledthereto via a dielectric horn (or lens) or an interface dielectric. Theantennas may be embedded in the ends of the dielectric medium.

An EHF-frequency signal may be launched into the coupler 300 from thetransmit transducer 312 at the transmitter end, propagating down thelong axis of the coupler 300 and out the other end, where it is receivedby the receive transducer 322. The dielectric coupler 300 may beflexible, and may include a connector element or fastener at one or bothends for connecting the coupler to one or more devices associated withthe transmitting and receiving communications chips (transceivers) 316and 326.

A dielectric coupler may include dielectric portions made of plastic orother materials having a dielectric constant of preferably at leastabout 2.0. Materials having higher dielectric constants may result inreduction of required dimensions due to a reduced wavelength of thesignal in that material. The dielectric material of the plastic cablethat may be at least partially coated in a layer having a low dielectricconstant or an electrically conductive layer to facilitate propagation,reduce interference, or to reduce the likelihood of shorting the signalbeing propagated down a long axis of the coupler.

The dielectric medium 302 may function as a transmission medium (such aswaveguide), and the EHF carrier may propagate along a long axis of thedielectric medium, maintaining a single polarization direction. An outersurface of the dielectric medium may be coated or covered with aconductive material (metal). The metal may isolate the dielectric mediumfrom external interference, and may serve as a conductive path forelectrical signals and/or power. Two or more metallizations 306, 308 mayextend along the length of the dielectric medium 302, such as forelectrical shielding, or for conveying power (in USB terminology, VBUS)and ground (GND). Stacked or layered structures may enable multiplesignal paths.

FIG. 3 is illustrative of a system comprising devices communicatingelectromagnetically, through one or more dielectric mediums, which mayinclude for example different plastic materials which may includehousings (240) for the device(s), as well as air (compare 230, FIG. 2).

The communications chip (transceiver) 316 may have electricalconnections 318 a and 318 b (which may collectively be referred to as“318”, shown as dashed lines) for connecting with the individualmetallizations 306 and 308 on the dielectric medium 302. Thecommunications chip (transceiver) 326 may have electrical connections328 a and 328 b (which may collectively be referred to as “328”, shownas dashed lines) for connecting with the individual metallizations 306and 308 on the dielectric medium 302. These electrical connections316/318 and 326/328 may supply power and ground such as from a hostdevice, along the link, for operating a bus-powered device.

These conductive paths 306 and 308 may provide power and ground (compare138 a and 138 b) for bus-powered devices.

For some applications, the communications chips 316 and 326 (withappropriate transducers, compare 312 and 322, respectively) maycommunicate directly with one another, over shorter distances, asdescribed in the '829 and '244 publications, without a coupler 300.Separate electrically conductive paths (compare 318 and 328) may beprovided to power bus-powered devices.

Some Embodiments

Transceivers (216 a/b, 316) were mentioned above, capable of convertingelectrical signal inputs into electromagnetic (EM) signal outputs tosupport an extremely high frequency (EHF) contactless communicationlink.

FIG. 4 shows a system comprising a half-duplex communications link 400between two devices 410 (compare 210) and 420 (compare 220). A firstdevice 410 receives an electrical signal (data) on a signal line(s) 418(compare 218). The data signal is encoded, such as using pulse codemodulation (PCM), and is provided to a transmitter (Tx) 402 whichtransmits the encoded data signal as an electromagnetic (EM) signal,such as in the EHF range. The EM signal is received at a receiver (Rx)424 of a second device 420, decoded, and provided as an electricalsignal (data) on a signal lines 428 (compare 228). In the reversedirection, the second device 420 receives an electrical signal (data) onthe signal line(s) 428. The data signal is encoded, such as using pulsecode modulation (PCM), and is provided to a transmitter (Tx) 422(compare 402) which transmits the encoded data signal as anelectromagnetic (EM) signal, such as in the EHF range. The EM signal isreceived at a receiver (Rx) 404 (compare 424) of the first device 410,decoded, and provided as an electrical signal (data) on the signalline(s) 418.

In the first device 402, a block 406 represents circuitry capable ofdetecting (measuring) a physical condition (such as voltage level) onthe signal line(s) 418, generating an electrical signal indicativethereof, and causing that signal to be encoded. The encoded signal maybe transmitted, such as out-of-band (OOB), by the transmitter 402 alongwith the aforementioned data as an electromagnetic (EM) signal to thesecond device 420. At the second device 420, the signal indicative ofthe physical condition of the signal line 418 is received, converted toan electrical signal, decoded, and provided to a block 426 whichrepresents circuitry capable of replicating a similar physical conditionon the signal line(s) 428.

In the reverse direction, in the second device 420, the block 426represents circuitry capable of detecting (measuring) a physicalcondition (such as voltage level) on the signal line(s) 428, generatingan electrical signal indicative thereof, and causing that signal to beencoded. The encoded signal may be transmitted, such as out-of-band(OOB), by a transmitter (Tx) 422 (compare 402) along with theaforementioned data as an electromagnetic (EM) signal to the firstdevice 410. At the first device 410, the signal indicative of thephysical condition of the signal line(s) 428 is received, converted toan electrical signal, decoded, and provided to the block 406 forreplicating a similar physical condition on the signal line(s) 418.

The blocks 406 and 426 may perform the functions of detecting a physical(electrical) condition such as voltage level on signal lines 418 and428, respectively, and imposing a similar physical (electrical)condition such as voltage level on the signal lines 428 and 418,respectively.

Additionally, protocol states may be tracked at the transmitter and thereceiver. For example, combining the protocol state with the electricalstate at the transmitters (Tx) to encode the complete electrical stateof an incoming signal. And, similarly, to recreate the completeelectrical signal at the receivers (Rx).

When initializing, the protocol state can be tracked on both sides ofthe link. An initial baseline (starting) protocol state may beestablished, before detecting the physical condition. This may be basedon protocol negotiation at the beginning of a communication session,such as information concerning speed, capabilities, drivers and thelike. Thereafter, the state and condition can be updated, in real time,based on what is being measured and received. The state may also changeafter a reset, or the like.

The transceivers may be enabled to detect a link partner whiledissipating minimal power. For example, the transmitter (Tx) may bepowered up periodically with a low duty cycle and set to send a constant‘1’ via a low-speed mode, then put to sleep. The receiver (Rx) may bepowered up periodically with a low duty cycle and set to listen for thebeacon. The receiver cycles should be such that the receiver power-onperiod spans at least two Tx beaconing cycles. The duty cycle of both Txand Rx must be such that the average current draw is <1 mA (implies a1/100th or lower duty cycle).

Energy output by the transmitters (TX) 402 and 422 may be in the EHFband, below FCC requirements for transmitting an identification codewhich would otherwise interrupt data flow. Reference is made to 47 CFR§15.255 (Operation within the band 57-64 GHz), incorporated by referenceherein.

The transceiver may be a half-duplex transceiver which canasynchronously convert a baseband signal into a modulated EHF carrierwhich is radiated from an internal antenna, or can receive anddemodulate the carrier and reproduce the original baseband signal.

The transceiver may comprise baseband input, output and signalconditioning circuitry (“Baseband blocks”), EHF generation, modulation,reception and demodulation circuitry (“RF Blocks”), Control I/Os andlogic (“Control blocks”) and Power Conditioning circuitry (“PowerBlocks”).

The transceiver may feature two operating modes: a high-speed mode,intended for use with DC-balanced differential signals, is suitable forsignals running from 100 Mb/s to 6.0 Gb/s and features support forenvelope-based Out-of-Band (OOB) signaling used in Serial-Attached-SCSI(SAS) and Serial Advanced Technology Attachment (SATA), as well aselectrical idle and Low-Frequency Periodic Signaling (LFPS) signals inPCI-Express (PCIe) and Universal Serial Bus version 3.0 (USB 3.0).Equalization for lossy PCB traces leading to and away from the device isincluded. Application information for this mode can be found in section6.1.

The transceiver may be implemented as a chip comprising a transmitter(Tx), a receiver (Rx) and related components. The transceiver chip mayuse an EHF carrier, at 30-300 GHz, such as 60 GHz carrier frequency.Transmit power and receive sensitivity may be controlled to minimize EMI(electromagnetic interference) effects and simplify FCC certification.The EHF carrier may penetrate a wide variety of commonly-usednon-conductive materials (glass, plastic, etc.).

In its transmit mode, the transceiver may operate functionally as arate- and protocol-transparent high-gain non-inverting buffer. The truedifferential inputs, such as from a USB bus, may be terminated on diewith 100Ω from true to complement and incorporate optional equalizationto counter high-frequency attenuation typical of PCB traces.

In its receive mode, the transceiver may operate functionally as ahigh-gain non-inverting buffer. The true differential outputs are sourceterminated on die with 50Ω per side and similarly incorporate optionalequalization to counter high frequency attenuation typical of PCBtraces. A signal detect function incorporated into the receiver (Rx) mayprovide a means of qualifying the strength of the received signal asbeing sufficient to receive error-free data through the high-speed datapath.

The transceiver may establish a low-latency protocol-transparentcommunication link supporting data rates up to 6.0 Gb/s, or higher. Thelink may be obtained through close-proximity coupling between twotransceiver chips, or over longer distances using a plastic cable (suchas 300), or the like. The transceiver chip features wide flexibility inthe relative orientation and spacing between the respective devices,thereby allowing operation across a broad range of placements.

Some features or characteristics of the transceiver may include:

-   -   Fully asynchronous signal path, less than 0.5 ns latency    -   100 Mb/s to 6.0 Gb/s bandwidth in a high-speed mode    -   Differential high-speed transmitter input, 100Ω differential        termination with switchable common-mode impedance for USB-SS and        PCIe Receive-detect compatibility    -   Signal detect output and muting of receive output on loss of        signal    -   Support for Out-of-Band (OOB) signaling for SATA and        Low-Frequency periodic Signaling (LFPS) for USB-SS and PCIe

The transceiver chip may be packaged in a conventional manner, such asin ultra-miniature BGA format. The antenna may be integrated into thepackage, or may be external to the package, or may be incorporated ontothe chip itself (such as in the manner of U.S. Pat. No. 6,373,447).

An exemplary communications module may comprise two or more transceiverchips, a CPLD (complex programmable logic device) or low-density FPGA(field-programmable gate array), a regulator, and a small number ofadditional discrete components, such as:

-   -   Programmable 1.5K pull-up on at least 1 but preferably 2 of the        IO—otherwise need to use an additional I/O in series with an        external resistor    -   Precision comparator capable of comparing voltages against a        reference    -   Device side may have a 1.5K (+/−5%) Ohm pullup resistor on D+    -   Host side may have a 15K (+/−5%) Ohm pulldown resistor on both        D+ and D−

Power and ground may be supplied by the first device 402 to the seconddevice 412 over a physical link providing an electrical (conductive)path between the two devices. For example, a connector 440, representedby the box drawn around the components 402, 404 and 406 may beassociated with the first device 410, such as mounted to a surface ofthe device 410 or at the end of a cable (not shown) extending from thedevice 410. Power (such as Vbus) and ground (such as GND) may besupplied to the connector 440, more particularly to corresponding twometallic (and electrically conductive) magnets 442 and 444,respectively, disposed within the connector 440. A connector 460,represented by the box drawn around the components 422, 424 and 426 maybe associated with the second device 420, such as mounted to a surfaceof the device 420 or at the end of a cable (not shown) extending fromthe device 420. Power (such as Vbus) and ground (such as GND) may bereceived by the connector 460, more particularly by corresponding twometallic (and electrically conductive) ferrous elements such as buttons462 and 464, respectively, disposed within the connector 460. Thetwo-headed arrows 452 and 454 represent conductive paths (compare 306,308) between the two devices 440 and 460. In this manner, in addition tocommunicating data electromagnetically (EM), the device 410, such as apersonal computer (PC) or laptop, functioning as a host, may providepower to a connected device 420, such as a scanner, webcam or the like.

FIG. 5 illustrates an exemplary method 500 of communicating data betweentwo devices, such as the devices 210 or 410 and 220 or 420. The methodis described in a greatly simplified manner, for illustrative clarity,as a sequence of steps.

In a first step 502, a given device (210, 410) determines (measures) aphysical (typically electrical) condition, such as voltage level, on one(or both) of the differential signal lines (218, 418) associated withthe given device (210, 410). As mentioned above, the physical conditionmay relate to how data may be exchanged between the two devices, such asmay pertain to speed an timing constraints.

In a next step 504, the given device (210, 410) prepares (encodes) asignal indicative of the measured physical condition for transmitting tothe other device. As mentioned above, this transmission may accompanythe transmission of data, and may for example be transmitted out-of-band(OOB).

In a next step 506, the given device (210, 410) transmits the signalindicative of the measured physical condition to the other device (220).As mentioned above, transmission may occur over an air gap, waveguide,or plastic cable (300).

In a next step 508, the other device (220, 420) receives and decodes thesignal indicative of the measured physical condition and determines(such as using a lookup table) a similar physical (typically electrical)condition to be applied on one (or both) of the differential signallines (228, 428) associated with the other device (220, 420).

In a last step 510, the other device (220, 420) replicates the similarphysical condition on one (or both) of the differential signal lines(228, 428) associated with the other device (220, 420).

Some Exemplary Deployments

FIG. 6A shows an exemplary application (deployment) 600 for some of thecommunications system techniques described herein, wherein a firstdevice which may be a computer (host) 602 is connected (linked) with asecond device 604 which may be a handset (such as a mobile telephone). Acable 610 has a mechanical (electrical) connector 612 (such as USBType-A) at one of its two ends for plugging into a corresponding jack(not shown) on the computer 602. This establishes an electricalconnection with the computer 602 for exchanging data (in eitherdirection, along the cable 610) with the handset 604. The other end ofthe cable 610 may be provided with an electromagnetic (EM) connector614, for example comprising transceivers (Tx, Rx) such as shown in FIG.4, for establishing a contactless link with the handset 604. The handset604 in this example may be enabled with suitable transceivers (Tx, Rx)for contactless communication (compare “Device 2” in FIG. 4).

Power may be provided from the host device 602 to the cable 610, via theconnector 612. Power may be provided from the cable 610 to the handset604 via magnets and electrical connections, as shown in FIG. 4, orwirelessly (inductively) via transformer coupling between a coil (notshown) in the connector 614 and a corresponding coil (not shown) in thedevice 604. Power may also flow in the opposite direction along thecable 610, from the device 604 to the device 602. The combination ofcontactless (EM) communication and wireless power enables the device 604to be completely enclosed, and protected from the environment.

FIG. 6B illustrates that (alternatively to the deployment shown in FIG.6A) power may be supplied to the cable 610 by a separate power supply(such as an AC adapter) 616, for powering the device (handset) 604. Inthis case, it is possible that data may not be transmitted through thecable 610, and the host device 602 need not be present.

While the invention(s) has been described with respect to a limitednumber of embodiments, these should not be construed as limitations onthe scope of the invention(s), but rather as examples of some of theembodiments. Those skilled in the art may envision other possiblevariations, modifications, and implementations that are should also beconsidered to be within the scope of the invention(s), based on thedisclosure(s) set forth herein, and as may be claimed.

What is claimed is:
 1. A method of communicating data comprising: at afirst device, determining an electrical condition of a first set ofsignal lines carrying data, and transmitting an electromagnetic (EM)signal indicative of the electrical condition associated with the data;wherein: the signal lines are configured for transporting aStandards-based protocol which is designed for communicating electricalsignals over a physical link.
 2. The method of claim 1, furthercomprising: at the first device, receiving an electromagnetic signalindicative of a second electrical condition associated with dataoriginated on second set of signal lines at a second device, andreplicating the second electrical condition at the first device.
 3. Themethod of claim 1, further comprising: at a second device, receiving theelectromagnetic signal indicative of the electrical condition andreplicating a similar electrical condition on a second set of signallines.
 4. The method of claim 2, wherein: the first and second devicesare not physically connected with one another.
 5. The method of claim 1wherein the Standards-based protocol is selected from the groupconsisting of USB, PCIe, SATA, SAS, MHL, HDMI, DP, Ethernet I2S, I2C,Thunderbolt, Quickpath, D-PHY, M-PHY and Hypertransport.
 6. The methodof claim 1, wherein the electromagnetic signal is transmitted withincriteria established by a Standards-based protocol.
 7. The method ofclaim 1, wherein the electromagnetic signal is transmitted with anenergy output below that of FCC requirements for transmitting anidentification code.
 8. The method of claim 1, wherein the first devicecommunicates electromagnetically, over an air gap.
 9. The method ofclaim 1, wherein the first device communicates electromagnetically,through one or more dielectric mediums.
 10. The method of claim 1,wherein the first device communicates over an electromagnetic interfacein an extremely high frequency (EHF) band.
 11. The method of claim 1,wherein the first device communicates by modulating and demodulating acarrier having a frequency of at least 30 GHz (gigahertz)
 12. The methodof claim 1, wherein the first device communicates data by modulating anddemodulating a carrier with a data rate which is greater than or equalto 1 Gbps (gigabits per second).
 13. The method of claim 2, furthercomprising: enclosing the device with a non-conducting barrier.
 14. Themethod of claim 2, wherein: the device is hermetically sealed by ahousing.
 15. The method of claim 1 wherein: the electromagnetic (EM)signal is transmitted through a dielectric cable.
 16. System forcommunicating data from signal lines configured for a Standards-basedprotocol which is designed for communicating electrical signals over aphysical link, characterized in that a first device comprises: means forconverting electrical signal inputs into electromagnetic (EM) signaloutputs to support an extremely high frequency (EHF) contactlesscommunication link; and means for determining an electrical condition ofa first set of signal lines carrying data and for transmitting anelectromagnetic (EM) signal indicative of the electrical conditionassociated with the data.
 17. The system of claim 16, furthercomprising: in the first device, means for receiving an electromagneticsignal indicative of a second electrical condition associated with dataoriginated on second set of signal lines at a second device, and forreplicating the second electrical condition at the first device.
 18. Thesystem of claim 16, further comprising: at the second device, means forreceiving the electromagnetic signal indicative of the electricalcondition and replicating a similar electrical condition on a second setof signal lines.
 19. The system of claim 16, further comprising: anon-conducting barrier enclosing the first device.